Acrylonitrile-butadiene-styrene copolymer resin (hereinafter referred to as ‘ABS resin’) is a resin in which a copolymer of styrenic monomer and acrylonitrile monomer grafted to butadiene rubbery polymer (hereinafter referred to as ‘g-ABS’) is dispersed in a matrix of styrene-acrylonitrile copolymer resin (hereinafter referred to as ‘SAN’). ABS resin has balanced properties of good processability, impact strength, rigidity, and melt strength, in addition to excellent colorability and gloss, and thus it has been widely used in the production of automobile goods, household electric/electronic appliances and OA supplies which need a good appearance.
When ABS resins are used for internal or external parts of electric/electronic goods such as blenders, washing machines, fans, and the like, which are subject to repeated stresses caused by driving of a motor, these parts should resist such stress and remain durable for extended use. Thus resins used to produce such products should also have good impact resistance and chemical resistance to strong chemicals such as acetic acid or diesel oil.
Polyester resins typically have a structure including short chains, and thus may not bend easily. Accordingly, polyester resins can have good rigidity, electrical properties, weather resistance and heat resistance, and the tensile strength of polyester resins may not be affected even after long term exposure to high temperatures. Further, crystalline polyester resins have good resistance to various chemicals such as diesel oil. However, the properties of polyester resins such as processability and impact resistance can degrade when they are exposed to acid or alkali for a long time at a high temperature due to their crystallinity.
Reinforcing agents such as glass fiber can be added to the polyester resins when polyester resins are employed as a structural material. If reinforcing agents are not added, it is difficult to use polyester resins as a structural material produced by injection molding. In addition, since polyester resins have low melt strength, their use is limited because it is difficult to use polyester resins in extrusion molding to produce thick sheets or pipes, other than films.
Recent attempts to prepare thermoplastic resins having good chemical resistance and impact resistance include alloying polyester resin with ABS resin. However, moisture degrades polyester at high temperatures and properties can be easily affected and deteriorated depending on the conditions of drying and molding. Hence, the alloy has a disadvantage in that it is difficult to control various conditions of drying and molding in order avoid adversely affecting the alloy.